Dendritic Spines: The Locus of Structural and Functional Plasticity

2014 ◽  
Vol 94 (1) ◽  
pp. 141-188 ◽  
Author(s):  
Carlo Sala ◽  
Menahem Segal
Keyword(s):  
Dendritic Spines ◽  
Synapse Formation ◽  
Complex Structure ◽  
Time Lapse ◽  
Spiny Neurons ◽  
Synaptic Interactions ◽  
Health And Disease ◽  
Spine Structure ◽  
And Function ◽  
Time Lapse Imaging

The introduction of high-resolution time lapse imaging and molecular biological tools has changed dramatically the rate of progress towards the understanding of the complex structure-function relations in synapses of central spiny neurons. Standing issues, including the sequence of molecular and structural processes leading to formation, morphological change, and longevity of dendritic spines, as well as the functions of dendritic spines in neurological/psychiatric diseases are being addressed in a growing number of recent studies. There are still unsettled issues with respect to spine formation and plasticity: Are spines formed first, followed by synapse formation, or are synapses formed first, followed by emergence of a spine? What are the immediate and long-lasting changes in spine properties following exposure to plasticity-producing stimulation? Is spine volume/shape indicative of its function? These and other issues are addressed in this review, which highlights the complexity of molecular pathways involved in regulation of spine structure and function, and which contributes to the understanding of central synaptic interactions in health and disease.

scholarly journals Microglia motility depends on neuronal activity and promotes structural plasticity in the hippocampus

2019 ◽  
Author(s):  
Felix C. Nebeling ◽  
Stefanie Poll ◽  
Lena C. Schmid ◽  
Manuel Mittag ◽  
Julia Steffen ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Dendritic Spines ◽  
Synapse Formation ◽  
Brain Parenchyma ◽  
Two Photon ◽  
Contact Rates ◽  
Health And Disease ◽  
The Impact ◽  
The Brain

AbstractMicroglia, the resident immune cells of the brain, play a complex role in health and disease. They actively survey the brain parenchyma by physically interacting with other cells and structurally shaping the brain. Yet, the mechanisms underlying microglia motility and their significance for synapse stability, especially during adulthood, remain widely unresolved. Here we investigated the impact of neuronal activity on microglia motility and its implication for synapse formation and survival. We used repetitive two-photon in vivo imaging in the hippocampus of awake mice to simultaneously study microglia motility and their interaction with synapses. We found that microglia process motility depended on neuronal activity. Simultaneously, more dendritic spines emerged in awake compared to anesthetized mice. Interestingly, microglia contact rates with individual dendritic spines were associated with their stability. These results suggest that microglia are not only sensing neuronal activity, but participate in synaptic rewiring of the hippocampus during adulthood, which has profound relevance for learning and memory processes.

scholarly journals N-cadherin: stabilizing synapses

2010 ◽  
Vol 189 (3) ◽  
pp. 397-398 ◽  
Author(s):  
Jyothi Arikkath
Keyword(s):  
Cell Adhesion ◽  
Cell Adhesion Molecule ◽  
Synapse Formation ◽  
Structure And Function ◽  
Cellular Mechanisms ◽  
Central Neurons ◽  
Spine Stabilization ◽  
Spine Structure ◽  
And Function ◽  
Spine Dynamics

Spines are sites of excitatory synapse formation in central neurons. Alterations in spine structure and function are widely believed to actively contribute to the cellular mechanisms of learning and memory. In this issue, Mendez et al. (2010. J. Cell Biol. doi:10.1083/jcb.201003007) demonstrate a pivotal role for the cell adhesion molecule N-cadherin in activity-mediated spine stabilization, offering a new mechanism for how spine dynamics and stability are regulated by activity in central neurons.

scholarly journals Examining Form and Function of Dendritic Spines

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kevin F. H. Lee ◽  
Cary Soares ◽  
Jean-Claude Béïque
Keyword(s):  
Dendritic Spines ◽  
Laser Scanning ◽  
Molecular Mechanisms ◽  
Laser Scanning Microscopy ◽  
Spine Morphology ◽  
Functional Changes ◽  
Form And Function ◽  
Spine Structure ◽  
And Function ◽  
The Relationship

The majority of fast excitatory synaptic transmission in the central nervous system takes place at protrusions along dendrites called spines. Dendritic spines are highly heterogeneous, both morphologically and functionally. Not surprisingly, there has been much speculation and debate on the relationship between spine structure and function. The advent of multi-photon laser-scanning microscopy has greatly improved our ability to investigate the dynamic interplay between spine form and function. Regulated structural changes occur at spines undergoing plasticity, offering a mechanism to account for the well-described correlation between spine size and synapse strength. In turn, spine structure can influence the degree of biochemical and perhaps electrical compartmentalization at individual synapses. Here, we review the relationship between dendritic spine morphology, features of spine compartmentalization and synaptic plasticity. We highlight emerging molecular mechanisms that link structural and functional changes in spines during plasticity, and also consider circumstances that underscore some divergence from a tight structure-function coupling. Because of the intricate influence of spine structure on biochemical and electrical signalling, activity-dependent changes in spine morphology alone may thus contribute to the metaplastic potential of synapses. This possibility asserts a role for structural dynamics in neuronal information storage and aligns well with current computational models.

scholarly journals Gut microbiome diversity detected by high-coverage 16S and shotgun sequencing of paired stool and colon sample

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Joan Mas-Lloret ◽  
Mireia Obón-Santacana ◽  
Gemma Ibáñez-Sanz ◽  
Elisabet Guinó ◽  
Miguel L. Pato ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Complex Structure ◽  
High Coverage ◽  
Cross Sectional ◽  
Microbiome Analysis ◽  
Hypervariable Regions ◽  
16S Gene ◽  
Faecal Samples ◽  
Health And Disease ◽  
And Function

AbstractThe gut microbiome has a fundamental role in human health and disease. However, studying the complex structure and function of the gut microbiome using next generation sequencing is challenging and prone to reproducibility problems. Here, we obtained cross-sectional colon biopsies and faecal samples from nine participants in our COLSCREEN study and sequenced them in high coverage using Illumina pair-end shotgun (for faecal samples) and IonTorrent 16S (for paired feces and colon biopsies) technologies. The metagenomes consisted of between 47 and 92 million reads per sample and the targeted sequencing covered more than 300 k reads per sample across seven hypervariable regions of the 16S gene. Our data is freely available and coupled with code for the presented metagenomic analysis using up-to-date bioinformatics algorithms. These results will add up to the informed insights into designing comprehensive microbiome analysis and also provide data for further testing for unambiguous gut microbiome analysis.

Fijiyama: a registration tool for 3D multimodal time-lapse imaging

2020 ◽  
Author(s):  
Romain Fernandez ◽  
Cédric Moisy
Keyword(s):  
Time Series Data ◽  
Time Lapse ◽  
Supplementary Information ◽  
Series Data ◽  
3D Registration ◽  
Extensive Documentation ◽  
Intractable Problems ◽  
Mri Scans ◽  
And Function ◽  
Time Lapse Imaging

Abstract Summary The increasing interest of animal and plant research communities for biomedical 3D imaging devices results in the emergence of new topics. The anatomy, structure and function of tissues can be observed non-destructively in time-lapse multimodal imaging experiments by combining the outputs of imaging devices such as X-ray CT and MRI scans. However, living samples cannot remain in these devices for a long period. Manual positioning and natural growth of the living samples induce variations in the shape, position and orientation in the acquired images that require a preprocessing step of 3D registration prior to analyses. This registration step becomes more complex when combining observations from devices that highlight various tissue structures. Identifying image invariants over modalities is challenging and can result in intractable problems. Fijiyama, a Fiji plugin built upon biomedical registration algorithms, is aimed at non-specialists to facilitate automatic alignment of 3D images acquired either at successive times and/or with different imaging systems. Its versatility was assessed on four case studies combining multimodal and time series data, spanning from micro to macro scales. Availability and implementation Fijiyama is an open source software (GPL license) implemented in Java. The plugin is available through the official Fiji release. An extensive documentation is available at the official page: https://imagej.github.io/Fijiyama Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Identification of astroglia-like cardiac nexus glia that are critical regulators of cardiac development and function

PLoS Biology ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. e3001444
Author(s):  
Nina L. Kikel-Coury ◽  
Jacob P. Brandt ◽  
Isabel A. Correia ◽  
Michael R. O’Dea ◽  
Dana F. DeSantis ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Cardiac Development ◽  
Time Lapse ◽  
Zebrafish Model ◽  
Single Cell Sequencing ◽  
Parasympathetic System ◽  
And Function ◽  
Time Lapse Imaging

Glial cells are essential for functionality of the nervous system. Growing evidence underscores the importance of astrocytes; however, analogous astroglia in peripheral organs are poorly understood. Using confocal time-lapse imaging, fate mapping, and mutant genesis in a zebrafish model, we identify a neural crest–derived glial cell, termed nexus glia, which utilizes Meteorin signaling via Jak/Stat3 to drive differentiation and regulate heart rate and rhythm. Nexus glia are labeled with gfap, glast, and glutamine synthetase, markers that typically denote astroglia cells. Further, analysis of single-cell sequencing datasets of human and murine hearts across ages reveals astrocyte-like cells, which we confirm through a multispecies approach. We show that cardiac nexus glia at the outflow tract are critical regulators of both the sympathetic and parasympathetic system. These data establish the crucial role of glia on cardiac homeostasis and provide a description of nexus glia in the PNS.

scholarly journals Achieving functional neuronal dendrite structure through sequential stochastic growth and retraction

2020 ◽  
Author(s):  
André Ferreira Castro ◽  
Lothar Baltruschat ◽  
Tomke Stürner ◽  
Amirhoushang Bahrami ◽  
Peter Jedlicka ◽  
...  
Keyword(s):  
Body Wall ◽  
Time Lapse ◽  
Membrane Curvature ◽  
Class I ◽  
List Type ◽  
Larval Body ◽  
And Function ◽  
Dendritic Branches ◽  
Time Lapse Imaging

AbstractClass I ventral posterior dendritic arborisation (c1vpda) proprioceptive sensory neurons respond to contractions in the Drosophila larval body wall during crawling. Their dendritic branches run along the direction of contraction, possibly a functional requirement to maximise membrane curvature during crawling contractions. Although the molecular machinery of dendritic patterning in c1vpda has been extensively studied, the process leading to the precise elaboration of their comb-like shapes remains elusive. Here, to link dendrite shape with its proprioceptive role, we performed long-term, non-invasive, in vivo time-lapse imaging of c1vpda embryonic and larval morphogenesis to reveal a sequence of differentiation stages. We combined computer models and dendritic branch dynamics tracking to propose that distinct sequential phases of targeted growth and stochastic retraction achieve efficient dendritic trees both in terms of wire and function. Our study shows how dendrite growth balances structure–function requirements, shedding new light on general principles of self-organisation in functionally specialised dendrites.In briefAn optimal wire and function trade-off emerges from noisy growth and stochastic retraction during Drosophila class I ventral posterior dendritic arborisation (c1vpda) dendrite development.HighlightsC1vpda dendrite outgrowth follows wire constraints.Stochastic retraction of functionally suboptimal branches in a subsequent growth phase.C1vpda growth rules favour branches running parallel to larval body wall contraction.Comprehensive growth model reproduces c1vpda development in silico.

scholarly journals JMJD6 Dysfunction Due to Iron Deficiency in Preeclampsia Disrupts Fibronectin Homeostasis Resulting in Diminished Trophoblast Migration

2021 ◽  
Vol 9 ◽  
Author(s):  
Sruthi Alahari ◽  
Abby Farrell ◽  
Leonardo Ermini ◽  
Chanho Park ◽  
Julien Sallais ◽  
...  
Keyword(s):  
Time Lapse ◽  
Lysosomal Degradation ◽  
Related Disorder ◽  
Novel Target ◽  
And Function ◽  
Time Lapse Imaging ◽  
Fibronectin Assembly ◽  
Degradation Time ◽  
Trophoblast Migration

The mechanisms contributing to excessive fibronectin in preeclampsia, a pregnancy-related disorder, remain unknown. Herein, we investigated the role of JMJD6, an O2- and Fe2+-dependent enzyme, in mediating placental fibronectin processing and function. MALDI-TOF identified fibronectin as a novel target of JMJD6-mediated lysyl hydroxylation, preceding fibronectin glycosylation, deposition, and degradation. In preeclamptic placentae, fibronectin accumulated primarily in lysosomes of the mesenchyme. Using primary placental mesenchymal cells (pMSCs), we found that fibronectin fibril formation and turnover were markedly impeded in preeclamptic pMSCs, partly due to impaired lysosomal degradation. JMJD6 knockdown in control pMSCs recapitulated the preeclamptic FN phenotype. Importantly, preeclamptic pMSCs had less total and labile Fe2+ and Hinokitiol treatment rescued fibronectin assembly and promoted lysosomal degradation. Time-lapse imaging demonstrated that defective ECM deposition by preeclamptic pMSCs impeded HTR-8/SVneo cell migration, which was rescued upon Hinokitiol exposure. Our findings reveal new Fe2+-dependent mechanisms controlling fibronectin homeostasis/function in the placenta that go awry in preeclampsia.

Impaired actin dynamics and suppression of Shank2-mediated spine enlargement in cortactin knockout mice

Microscopy ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 44-52
Author(s):  
Shinji Tanaka ◽  
Yasutaka Masuda ◽  
Akihiro Harada ◽  
Shigeo Okabe
Keyword(s):  
Dendritic Spines ◽  
Actin Polymerization ◽  
Postsynaptic Density ◽  
Time Lapse ◽  
Suppressive Effect ◽  
Actin Dynamics ◽  
Spine Morphology ◽  
Actin Organization ◽  
Actin Turnover ◽  
Time Lapse Imaging

Abstract Cortactin regulates actin polymerization and stabilizes branched actin network. In neurons, cortactin is enriched in dendritic spines that contain abundant actin polymers. To explore the function of cortactin in dendritic spines, we examined spine morphology and dynamics in cultured neurons taken from cortactin knockout (KO) mice. Histological analysis revealed that the density and morphology of dendritic spines were not significantly different between wild-type (WT) and cortactin KO neurons. Time-lapse imaging of hippocampal slice cultures showed that the extent of spine volume change was similar between WT and cortactin KO neurons. Despite little effect of cortactin deletion on spine morphology and dynamics, actin turnover in dendritic spines was accelerated in cortactin KO neurons. Furthermore, we detected a suppressive effect of cortactin KO on spine head size under the condition of excessive spine enlargement induced by overexpression of a prominent postsynaptic density protein Shank2. These results suggest that cortactin may have a role in maintaining actin organization by stabilizing actin filaments near the postsynaptic density.

scholarly journals Dual function of perivascular fibroblasts in vascular stabilization in zebrafish

PLoS Genetics ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. e1008800
Author(s):  
Arsheen M. Rajan ◽  
Roger C. Ma ◽  
Katrinka M. Kocha ◽  
Dan J. Zhang ◽  
Peng Huang
Keyword(s):  
Blood Vessels ◽  
Time Lapse ◽  
Cell Types ◽  
Dual Function ◽  
Dual Roles ◽  
Vascular Integrity ◽  
Genetic Ablation ◽  
Mural Cells ◽  
And Function ◽  
Time Lapse Imaging

Blood vessels are vital to sustain life in all vertebrates. While it is known that mural cells (pericytes and smooth muscle cells) regulate vascular integrity, the contribution of other cell types to vascular stabilization has been largely unexplored. Using zebrafish, we identified sclerotome-derived perivascular fibroblasts as a novel population of blood vessel associated cells. In contrast to pericytes, perivascular fibroblasts emerge early during development, express the extracellular matrix (ECM) genes col1a2 and col5a1, and display distinct morphology and distribution. Time-lapse imaging reveals that perivascular fibroblasts serve as pericyte precursors. Genetic ablation of perivascular fibroblasts markedly reduces collagen deposition around endothelial cells, resulting in dysmorphic blood vessels with variable diameters. Strikingly, col5a1 mutants show spontaneous hemorrhage, and the penetrance of the phenotype is strongly enhanced by the additional loss of col1a2. Together, our work reveals dual roles of perivascular fibroblasts in vascular stabilization where they establish the ECM around nascent vessels and function as pericyte progenitors.

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